Pelvic flexion/extension and its impact on functional acetabular alignment and stability following total hip replacement.

PURPOSE: Dislocation following total hip arthroplasty (THA) remains a significant clinical problem and can occur even with optimal implant alignment. We hypothesized that different patterns of pelvic flexion/extension (PFE) during daily activities may influence acetabular alignment and contribute to impingement and instability following THA. Recently, there has been an increased interest in spinopelvic alignment and its impact on THA. Therefore, this study aimed to identify different patterns of PFE that could be predictive of instability following THA. METHODS: A range of motion (ROM) simulator was used to demonstrate the effects of different patterns of PFE on ROM and impingement. The findings were applied to PFE measurements obtained from 84 patients in standing and sitting positions. RESULTS: Three different categories of PFE were identified: normal, hypermobile, and stiff. ROM simulator revealed that changes in PFE had affected ROM and impingement significantly. Patients in the stiff pelvis category, even with "optimal" implant alignment, were more susceptible to implant impingement. CONCLUSIONS: The different patterns of PFE during daily activities could affect acetabular alignment and stability following THA. We propose a classification system that can identify different types of PFE and predict their effects on the stability of prostheses following THA. Hence, we believe that patients with unfavorable PFE may require modified cup alignment.

Comparison of Asymptomatic and Symptomatic Adverse Local Tissue Reaction in Patients With Head-Neck Taper Corrosion.

BACKGROUND: Diagnosis of adverse local tissue reaction (ALTR) in metal-on-polyethylene (MoP) total hip arthroplasty (THA) secondary to head-neck taper corrosion is challenging. The purpose of this study is to compare differences between asymptomatic and symptomatic ALTR in an observational cohort, including presentation, metal ion differences, and metal artifact reduction sequence (MARS) magnetic resonance imaging (MRI) findings. METHODS: We performed a retrospective review of an observational cohort of 492 MoP THA patients at increased risk of developing ALTR. Ninety-four patients underwent revision arthroplasty for ALTR. Patients were stratified into symptomatic and asymptomatic ALTR groups. Presentation, metal ion levels, and imaging findings were compared. RESULTS: For patients with confirmed ALTR, 41% were asymptomatic. There was a statistically significant difference in the serum chromium levels between symptomatic and asymptomatic ALTR patients (2.2 µg/L vs 3.1 µg/L, P = .05). There was no statistically significant difference between the serum cobalt levels or MRI findings in these 2 groups. We observed that extracapsular disease associated with ALTR could be misinterpreted as trochanteric bursitis. CONCLUSION: Almost half of the MoP THA ALTR cases identified were asymptomatic. Cobalt levels could not differentiate between symptomatic and asymptomatic pseudotumor formation. Symptomatic and asymptomatic MoP ALTRs have similar MARS MRI characteristics. Our findings suggest that it is essential to risk stratify patients who could potentially have ALTR based on implant type, symptoms, ion levels, and MARS MRI.

Drivers of the Variation in Prosthetic Implant Purchase Prices for Total Knee and Total Hip Arthroplasties.

BACKGROUND: Previous studies have documented wide variation in health care spending and prices; however, the causes for the variation in supply purchase prices across providers are not well understood. The purpose of this study was to determine the drivers of variation in prosthetic implant purchase prices for primary total knee and hip arthroplasties (TKA and THA, respectively) across providers. METHODS: We obtained retrospective data from 27 hospitals on the average prosthetic implant purchase prices for primary TKAs and THAs over the 12 months ending September 30, 2013, as well as data on a range of independent potential explanatory variables. Each hospital performed at least 200 primary total joint arthroplasties per year. The multivariate seemingly unrelated regression approach was used to evaluate the impact of the variables on purchase price for each type of implant. RESULTS: The average purchase price at the hospital at the 90th percentile was 2.1 times higher for TKAs and 1.7 times higher for THAs than that at the hospital at the 10th percentile. The use of a hospital-physician committee for implant vendor selection and negotiation was associated with 17% and 23% lower implant purchase prices (P < .05) for TKAs and THAs, respectively, relative to hospitals that did not have this collaborative approach. CONCLUSION: The use of a joint hospital-physician committee is a potential strategy for achieving lower average purchase prices for prosthetic implants. Policies to increase hospital-physician collaboration may lead to lower average purchase prices in this market.

Trunnion Failure of the Recalled Low Friction Ion Treatment Cobalt Chromium Alloy Femoral Head.

BACKGROUND: Gross trunnion failure (GTF) is a rare complication in total hip arthroplasty (THA) reported across a range of manufacturers. Specific lots of the Stryker low friction ion treatment (LFIT) anatomic cobalt chromium alloy (CoCr) V40 femoral head were recalled in August 2016. In part, the recall was based out of concerns for disassociation of the femoral head from the stem and GTF. METHODS: We report on 28 patients (30 implants) with either GTF (n = 18) or head-neck taper corrosion (n = 12) of the LFIT CoCr femoral head and the Accolade titanium-molybdenum-zirconium-iron alloy femoral stems. All these cases were associated with adverse local tissue reactions requiring revision of the THA. RESULTS: In our series, a conservative estimate of the incidence of failure was 4.7% (n = 636 total implanted) at 8.0 ± 1.4 years from the index procedure. Failures were associated with a high-offset 127° femoral stem neck angle and increased neck lengths; 43.3% (13 of 30) of the observed failures included implant sizes outside the voluntary recall (27.8% [5 of 18] of the GTF and 75.0% [8 of 12] of the taper corrosion cases). Serum cobalt and chromium levels were elevated (cobalt: 8.4 ± 7.0 µg/mL; chromium: 3.4 ± 3.3 µ/L; cobalt/chromium ratio: 3.7). The metal artifact reduction sequence magnetic resonance imaging demonstrated large cystic fluid collections typical with adverse local tissue reactions. During revision, a pseudotumor was observed in all cases. Pathology suggested a chronic inflammatory response. Impending GTF could be diagnosed based on aspiration of black synovial fluid and an oblique femoral head as compared with the neck taper on radiographs. CONCLUSION: In our series of the recalled LFIT CoCr femoral head, the risk of impending GTF or head-neck taper corrosion should be considered as a potential diagnosis in a painful LFIT femoral head and Accolade titanium-molybdenum-zirconium-iron alloy THA with unknown etiology. Almost half of the failures we observed included sizes outside of the voluntary recall.

Determining the True Cost to Deliver Total Hip and Knee Arthroplasty Over the Full Cycle of Care: Preparing for Bundling and Reference-Based Pricing.

The Affordable Care Act accelerates health care providers' need to prepare for new care delivery platforms and payment models such as bundling and reference-based pricing (RBP). Thriving in this environment will be difficult without knowing the true cost of care delivery at the level of the clinical condition over the full cycle of care. We describe a project in which we identified true costs for both total hip and total knee arthroplasty. With the same tool, we identified cost drivers in each segment of care delivery and collected patient experience information. Combining cost and experience information with outcomes data we already collect allows us to drive costs down while protecting outcomes and experiences, and compete successfully in bundling and RBP programs.

Topical versus intravenous tranexamic acid in total knee arthroplasty.

The objective of this study is to compare the effectiveness of intravenous versus topical application of tranexamic acid in patients undergoing knee arthroplasty. All patients who underwent primary knee arthroplasty at our total joint center over a 12-month period were included in the study. One surgeon utilized 1 g of IV TXA at time of incision in all patients (n=373) except those with a documented history of venous thromboembolism (VTE). Two surgeons utilized a topical application of TXA for all patients without exception (n=198) in which the joint was injected after capsular closure with 3 g TXA/100 mL saline. The transfusion rate was 0% in the topical group vs. 2.4% in the IV group and this was statistically significant (P<0.05).

Developing a pathway for high-value, patient-centered total joint arthroplasty.

BACKGROUND: Total joint arthroplasty (TJA) is one of the most widely performed elective procedures; however, there are wide variations in cost and quality among facilities where the procedure is performed. QUESTIONS/PURPOSES: The purposes of this study were to (1) develop a generalizable clinical care pathway for primary TJA using inputs from clinical, academic, and patient stakeholders; and (2) identify system- and patient-level processes to provide safe, effective, efficient, and patient-centered care for patients undergoing TJA. METHODS: We used a combination of quantitative and qualitative methods to design a care pathway that spans 14 months beginning with the presurgical office visit and concluding 12 months after discharge. We derived care suggestions from interviews with 16 hospitals selected based on readmission rates, cost, and quality (n = 10) and author opinion (n = 6). A 32-member multistakeholder panel refined the pathway during a 1-day workshop. Participants were selected based on leadership in orthopaedic (n = 4) and anesthesia (n = 1) specialty societies; involvement in organizations specializing in safety and high reliability care (n = 3), lean production/consumption of care (n = 3), and patient experience of care (n = 3); membership in an interdisciplinary care team of a hospital selected for interviewing (n = 8); recent receipt of a TJA (n = 1); and participation in the pathway development team (n = 9). RESULTS: The care pathway includes 40 suggested processes to improve care, 37 techniques to reduce waste, and 55 techniques to improve communication. Central themes include standardization and process improvement, interdisciplinary communication and collaboration, and patient/family engagement and education. Selected recommendations include standardizing care protocols and staff roles; aligning information flow with patient and process flow; identifying a role accountable for care delivery and communication; managing patient expectations; and stratifying patients into the most appropriate care level. CONCLUSIONS: We developed a multidisciplinary clinical care pathway for patients undergoing TJA based on principles of high-value care. The pathway is ready for clinical testing and context-specific adaptation. LEVEL OF EVIDENCE: Level V, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.

Utilizing complexity science to drive practice change through patient- and family-centered care.

Complexity science applied through a 6-step patient- and family-centered care methodology provides a practical framework for achieving meaningful change in organizations. This approach was used to improve the preoperative preparation experience of patients undergoing total joint arthroplasty in an orthopedic specialty hospital.

Optimizing PROM Implementation in Orthopedic Clinics for Longitudinal Outcome Monitoring: Lessons from a Multisite Study.

BACKGROUND: Systematic patient-reported outcome measure (PROM) collection is challenging for clinics, particularly when patients are not in the office. The Arthritis care through Shared Knowledge (ASK) study deployed multimodal approaches to collect PROMs using a clinical microsystem framework. CONCEPTUAL MODEL: Informed by the clinical microsystem model, the authors coached 12 orthopedic practices to implement shared processes to support best practices for PROM collection and use. Orthopedic sites collected PROMs from new patients before the first office visit; patients completed the PROM from home via an online assessment in a personalized e-mail. Site staff placed follow-up phone reminders. At 6 and 12 months after the visit, PROMs were collected from home, prompted by an e-mail or phone call. PERFORMANCE OUTCOMES: Of the 25,043 new patients identified by clinical sites during the study enrollment, approximately 60% completed a pre-visit PROM-36.6% completed the online PROM after receiving a single automated e-mail, and an additional 31.1% completed the PROM after receiving a text, an e-mail, or a phone call from the staff. The remaining 32.2% of PROMs were collected on arrival at the office. Of patients completing PROMs, 11,140 were eligible to participate in longitudinal collection, and 51.3% consented. Of these, approximately 84% completed a 6-month survey, more than 83% completed a 12-month survey, and more than 91% completed either a 6-month PROM, a 12-month PROM, or both. LEARNING: This study illustrates that a multimodal approach to PROM collection using a clinical microsystem approach sustainably supports PROM completion rates. Further efforts are needed to define strategies to engage all patients in understanding and reporting PROMs to inform their care.

Care experience-based methodologies: performance improvement roadmap to value-driven health care.

BACKGROUND: The literature contains proposals for creating value by creating exceptional patient experiences rather than simply improving services. However, few articles describe replicable applications focused on the patient experience. QUESTIONS/PURPOSES: We (1) describe the refinement and exportation of an approach that focuses on the patient and family experience; and (2) report changes in patient satisfaction, infection rates, length of stay, mortality rates, clinical indicators, staff turnover, and cost. METHODS: The Patient and Family-Centered Care Methodology and Practice (PFCC M/P) is a six-step process: (1) selecting a care experience needing improvement; (2) establishing a guiding council; (3) evaluating the current state; (4) developing a permanent working group; (5) creating a shared vision of the ideal experience; and (6) identifying improvement projects to address the gap between the current and ideal experience. We assessed patient satisfaction, changes in clinical indicators, staff turnover, and cost in three clinical programs. RESULTS: In TJA, patient satisfaction is at the 99th percentile; length of stay, infection rates, and mortality rates are substantially better than the national average. In trauma, patient satisfaction increased, time in cervical collars decreased, staff turnover decreased, and the incidence of lost patient belongings was eliminated. In orthopaedic spine, patient satisfaction is higher than the national average, average time for transfer to bed decreased (%), length of stay decreased, and average discharge time decreased. Each of these would have a positive impact on cost. CONCLUSIONS: PFCC M/P offers a road map for redefining value as what is important to patients and families.

Predictors of Adverse Local Tissue Reaction in a High-Risk Population.

BACKGROUND: Adverse local tissue reaction (ALTR) is a recognized complication of total hip arthroplasty (THA) with metal-on-polyethylene (MoP) bearing surface implants. Specific models of THA implants have been identified as having a higher incidence of ALTR. The purpose of this study is to determine if serum metal levels, patient symptoms, implant factors, and imaging findings can be predictive of ALTR within this high-risk population. METHODS: We retrospectively reviewed an observational cohort of 474 patients who underwent MoP THA and were at increased risk of having ALTR. Patients were stratified based on the presence or absence of ALTR. Patient symptoms, serum metal ions, implant head offset, and imaging findings were compared. RESULTS: Patients with ALTR were more likely to be symptomatic (52.9% vs 9.9%, P < .0001). The presence of ALTR was associated with significantly higher serum cobalt and chromium levels (6.2 ppb vs 3.6 ppb, P < .0001; 2.3 ppb vs 1.2 ppb, P < .0001). Head offsets greater than 4 mm were associated with a higher prevalence of ALTR (53% vs 38%, P = .05). On metal artifact reduction sequence magnetic resonance imaging, patients with ALTR had larger effusions (4.7 cm vs 2.1 cm, P < .001) and a higher incidence of trochanteric bursitis (47% vs 16%, P < .001). CONCLUSIONS: In high-risk MoP implants, serum cobalt and chromium levels are elevated, even in patients without ALTR. A larger femoral head offset is a risk factor for the development of ALTR. Our study suggests that patients presenting with painful THA and elevated metal ions require risk stratification based on patient symptoms, metal artifact reduction sequence magnetic resonance imaging findings, and implant factors.

Effectiveness of Later-Stage Exercise Programs vs Usual Medical Care on Physical Function and Activity After Total Knee Replacement: A Randomized Clinical Trial.

Importance: Several functional limitations persist after total knee replacement (TKR). Intensive exercise programs could resolve these limitations but are not well tolerated by many patients until a later stage (>2 months) after surgery. Evidence for exercise at a later stage after TKR is limited. Objectives: To compare the effectiveness of later-stage exercise programs after TKR and to explore heterogeneity of treatment effects. Design, Setting, and Participants: Three-arm single-blind randomized clinical trial (January 7, 2015, to November 9, 2017) using an intent-to-treat approach with follow-ups at 3 months and 6 months. The setting was Allegheny County, Pennsylvania (an outpatient physical therapy clinic and 4 community centers). Participants had primary TKR performed more than 2 months previously, were 60 years or older, experienced moderate functional limitations, and were medically cleared to exercise. Interventions: Clinic-based physical therapy exercise (physical therapy arm), community-based group exercise (community arm), and usual care (control arm). The control arm continued their usual care, whereas the exercise arms participated in supervised exercise programs lasting 12 weeks. Main Outcomes and Measures: The primary outcome was arm differences in the Western Ontario and McMaster Universities Osteoarthritis Index-Physical Function (WOMAC-PF) at 3 months. The secondary outcomes included performance-based tests germane to knee replacement and additional surveys of physical function. Data were analyzed by linear mixed models and responder analysis. Results: A total of 240 participants (mean [SD] age, 70 [7] years; 61.7% female) were allocated to physical therapy (n = 96), community exercise (n = 96), or control (n = 48). All 3 arms demonstrated clinically important improvement. At 3 months, between-arm analyses for the WOMAC-PF demonstrated no differences between physical therapy and community (-2.2; 98.3% CI, -4.5 to 0.1), physical therapy and control (-2.1; 98.3% CI, -4.9 to 0.7), and community and control (0.1; 98.3% CI, -2.7 to 2.9). Performance-based tests demonstrated greater improvement in the physical therapy arm compared with both the community (0.1 z score units; 98.3% CI, 0.0-0.2) and control (0.3 z score units; 98.3% CI, 0.1-0.4) arms and the community arm compared with the control arm (0.2 z score units; 98.3% CI, 0.0-0.3). The physical therapy arm had more than 17.7% responders than the community arm and more than 19.0% responders than the control arm. There was no difference in responder rates between the community and control arms. Conclusions and Relevance: Based on the primary outcome, participation in late-stage exercise programs after TKR offered no benefit over usual care. The benefits of physical therapy identified by the secondary outcomes and responder analysis require confirmation. Trial Registration: ClinicalTrials.gov Identifier: NCT02237911.

Effect of Comprehensive Behavioral and Exercise Intervention on Physical Function and Activity Participation After Total Knee Replacement: A Pilot Randomized Study.

OBJECTIVE: To test the feasibility of a comprehensive behavioral intervention (CBI) program that combines intense exercises with an education program, to be implemented at a later stage (3 months) following total knee replacement (TKR), and to get a first impression of the effects of the CBI as compared to a standard of care exercise (SCE) program on the outcomes of physical function and physical activity. METHODS: A total of 44 subjects participated in a 3-month program of either CBI or SCE, followed by 3 months of a home exercise program. Outcomes of physical function and physical activity were measured at baseline and at 6-month followup. Analysis of variance was used to compare statistical differences between groups, whereas responder analyses were used for clinically important differences. RESULTS: The CBI was found to be safe and well tolerated. As compared to the SCE group, the CBI group had less pain (P = 0.035) and better physical function based on the Short Form 36 health survey (P = 0.017) and the single-leg stance test (P = 0.037). The other outcome measures did not demonstrate statistically significant differences between the 2 groups. Results from the responder analysis demonstrated that the CBI group had a 36% higher rate of responders in physical function as compared to the SCE group. Also, the CBI group had 23% more responders in the combined domains of physical function and physical activity. CONCLUSION: The CBI program is feasible and improves physical function and physical activity in patients several months after TKR. Larger pragmatic randomized trials are needed to confirm the results of this study.

A kinematic model for calculating cup alignment error during total hip arthroplasty.

Reduced range of motion, prosthetic impingement, and joint dislocation can all result from misalignment of the acetabular component (i.e. cup alignment) in patients undergoing total hip arthroplasty. Most methods for acetabular component alignment are designed to provide 45-50 degrees abduction and 15-25 degrees of operative anteversion (also known as flexion) with respect to the anterior pelvic plane coordinate system. Yet in most cases, this coordinate system is not assigned properly, due to differences in patient anatomy and improper positioning in the operating room. This misalignment can result in an error in the cup alignment, which can cause the above-mentioned consequences. This work presents a complete mathematical formulation for the analysis of the inaccuracies related to the anterior pelvic plane axes (APPA) definition and their effect on final cup orientation. We do this by introducing a method taken from Kinematics of Mechanisms, and by representing the errors in the APPA as three concurrent axes of rotation, followed by the version and abduction rotations which are defined relative to the previous rotations. We also present a sensitivity analysis of the results by introducing differential changes between sequential coordinate frames, which simulates the errors in the APPA and their effect on cup orientation. Finally, we demonstrate a computational method which provides corrected version and abduction angles to achieve the desired cup orientation, given that the actual measurement errors are known.

Measurements of acetabular cup position and pelvic spatial orientation after total hip arthroplasty using computed tomography/radiography matching.

This study presents a clinical validation of postoperative measurements of acetabular cup alignment following total hip arthroplasty (THA). The methodology was based on concurrent anatomic three-dimensional (3D) measurements of both the acetabular cup alignment and pelvic orientation, using an original CT/X-ray matching algorithm named Xalign. The subjects were 19 patients who had undergone bilateral THA using CT-based surgical navigation. All patients had postoperative pelvic CT scans and multiple antero-posterior (AP) pelvic X-rays. Using a proprietary software algorithm, the X-rays included in the study were matched with the corresponding postoperative CT scans. The goal of this method was to allow 3D anatomic pelvic and acetabular measurements on two-dimensional AP X-rays. The postoperative cup abduction, version and pelvic flexion angles were determined in three different ways: using CT images directly, applying the Xalign method, and finally by performing conventional (abduction only) measurements on AP pelvic X-rays. The cup orientation measured on CT images was taken as the ground truth. The Xalign measurement errors were defined as the difference between the CT cup values and those obtained by applying the matching method. The mean cup abduction error was 0.85 degrees +/- 1.3 degrees (+/- standard deviation) and the mean version error was 0.01 degrees +/- 1.99 degrees . Conventionally measured cup abduction ranged from 44 degrees to 62 degrees and correlated significantly (p = 0.001, r = -0.5) with pelvic flexion angle, proving the linear negative correlation between pelvic flexion and the error in conventional radiographic cup measurements. The Xalign method offered reasonable accuracy for cup orientation, and allowed cup and pelvic 3D anatomic measurements at different times.

A case for integrating the Patient and Family Centered Care Methodology and Practice in Lean healthcare organizations.

Many healthcare organizations using Lean are becoming interested in the Patient and Family Centered Care Methodology and Practice (PFCC M/P). We suggest that integrating the two approaches can accelerate the pace of improvement and provide a powerful mechanism to keep the patient and family as the primary focus of improvement activities. We describe the two approaches and note the ways in which they are complementary. We then discuss the ways in which integrating the PFCC M/P adds value to patients, families, providers, and organizations and accelerates transformation. Finally, we suggest ways to implement PFCC M/P within Lean healthcare organizations.

Dose-Associated Changes in Gait Parameters in Response to Exercise Programs after Total Knee Arthroplasty: Secondary Analysis of Two Randomized Studies.

BACKGROUND: Rehabilitation plays an important role to improve the outcomes of total knee arthroplasty (TKA). Evidence about the appropriate dose of exercise to recover gait dysfunction after TKA is limited. We posed the research question: In patients during the post-acute stage after TKA, is increased dose of exercise associated with larger improvements in gait parameters such as step length and single support time? METHODS: This was a secondary analysis from two randomized studies on exercise after TKA to investigate dose-dependence of gait parameters in response to exercise. Participants were 50 years or older who underwent unilateral TKA at least two months prior. They participated in 2 months of supervised exercises followed by 4 months of a home exercise program. The primary outcome was change in gait parameters from baseline to 6 months. Participants were divided in three groups according to the dose of exercise: group 1 (light-to-moderate intensity exercise), group 2 (high intensity + functional exercise), and group 3 (high intensity + functional + balance exercise). Jonckheere-Terpstra test was used to test if the magnitude of changes in gait parameters increased from group 1 to group 3 in an ordered fashion. RESULTS: Increased dose of exercise was associated with progressive increases in step length in the operated-limb (p=0.008) and decreases in step length in the non-operated limb (p=0.011). Increased dose of exercise was associated with ordinal decreases in loading response time (p=0.049) and increases in single-leg support time (p=0.021) on the operated- limb, but not on the non-operated-limb. Increased dose of exercise was associated with decreases in unloading time on the non-operated-limb (p=0.011) but not on the operated-limb (p=0.400). CONCLUSIONS: Significant dose-response of exercise on gait parameters support the promotion of more intensive exercise programs that combine functional and balance training programs after TKA.

Computer-assisted orthopaedic surgery: minimally invasive hip and knee reconstruction.

Joint reconstructive surgery is experiencing new and important developments. Less and minimally invasive techniques for hip and knee replacement have been described recently by several investigators. They have outlined not only the positive aspects, but also some of the difficult challenges. Accuracy and safety of the surgery could be increased, despite the smaller approaches, with navigation tools. Although promising,the initial clinical experience is limited and needs to be supported by further, prospective analysis.

Less invasive total hip arthroplasty using navigational tools.

Although traditional total hip arthroplasty offers good visualization of bony landmarks and allows for the accurate orientation and fixation of implants, these benefits are achieved at the expense of extensive soft-tissue dissection and can result in postoperative complications and a delayed return to full function. To address these disadvantages, navigational tools were coupled with a mini-incision technique that allowed accurate bone preparation and orientation of the implant components without direct visualization of the bony landmarks. Additionally, image-guided systems provide three-dimensional information before and during surgery, making it possible to know, in real time, the orientation of implants and to visualize the full bony anatomy. This "computer-enhanced vision" allows surgeons to perform less invasive and eventually minimally invasive total hip arthroplasty with improved accuracy.